Balloon dilatation devices have been used to treat constricted paranasal sinus passageways for several years. These balloon dilatation devices generally involve the use of an inflatable balloon located at the distal end of a catheter such as a balloon catheter. The balloon catheter may include a substantially rigid inner guide member and a movable shaft coupled to a balloon that is slidably mounted on the rigid inner guide member. The inner guide member might be a stainless steel wire or flexible plastic member to facilitate the location and access of sinus ostia, and is generally introduced through the nostril into the target sinus under endoscopic visualization. A flexible wire or flexible plastic member is introduced through the inner guide member and gently advanced into the target sinus. The balloon catheter generally slides over the inner guide member and the flexible wire, and it is positioned across the constricted ostium. The balloon is gradually inflated, generally with a liquid medium, to gently restructure the constricted ostium. The balloon is then deflated and removed, and an irrigation system may be advanced to wash the sinus with a sterile solution. Generally, this procedure is referred to as Balloon Sinuplasty™, and a number of U.S. patents and patent applications including U.S. Pat. Nos. 7,645,272, 7,654,997, and 7,803,150 describe various embodiments of the medical procedure and devices used in the performance of such procedure.
Such conventional methods and apparatus, however, have significant drawbacks. Generally, these methods do not provide a way to advance the inner guide member and balloon catheter easily and effectively, especially in patients with constricted nostrils or deviated septums or constricted openings to the middle meatus. Additionally, traditional balloon catheters distribute the force equally on the surrounding structures during the dilatation process. In some cases, the balloon catheter is located near critical structures that can be easily damaged by the omnidirectional force applied by traditional balloon catheters. Therefore, there has been a long-desired but unresolved need for a system or method that could direct the force applied by a balloon catheter during the dilatation process for protecting delicate structures and also for aiding in the process of accessing the target paranasal sinus.